2000/03/17 by Maurice Bruynooghe, Henk Vandecasteele, D. Andre de Waal +1
Computer Science · #cs.LO #cs.AI
published as Journal of Functional and Logic Programming, Vol. 1999, 1-35, 1999 · 32 pages including appendix. A preliminary version appeared in proceedings PLILP/ALP98 (Springer LNCS 1490) This version, without appendix appeared in Journal Functional and Logic Programming 1999
arxiv created 2000/03/17 · arxiv updated 2009/11/30
In solving a query, the SLD proof procedure for definite programs sometimes searches an infinite space for a non existing solution. For example, querying a planner for an unreachable goal state. Such programs motivate the development of methods to prove the absence of a solution. Considering the definite program and the query ``<- Q'' as clauses of a first order theory, one can apply model generators which search for a finite interpretation in which the program clauses as well as the clause ``false <- Q'' are true. This paper develops a new approach which exploits the fact that all clauses are definite. It is based on a goal directed abductive search in the space of finite pre-interpretations for a pre-interpretation such that ``Q'' is false in the least model of the program based on it. Several methods for efficiently searching the space of pre-interpretations are presented. Experimental results confirm that our approach find solutions with less search than with the use of a first order model generator.